Cluster system and an error recovery method thereof

Abstract

A cluster system includes a transmission side server cluster consisting of a plurality of computers, one of which is selected as a transmitting computer and at least another one of which is selected as a standby computer. When the transmitting computer transmits a message it received to a receiving side server, it also transmits the message to the standby computer that was selected, based on load information for all computers other than the transmitting one in the transmission side server cluster.

1 . A cluster system comprising: 
 a transmission side server cluster consisting of a plurality of computers;    a receiving side server cluster consisting of a plurality of computers; and    a network that interconnects both said transmission side server cluster and said receiving side server cluster,    wherein one computer which is included in said transmission side server cluster and has received a message (which is hereinafter referred to as a “transmitting computer”) selects a second computer (hereinafter referred to as a “standby computer”) from among the computers in said transmission side server cluster, based on load information, and transmits the received message to said standby computer when transmitting the message to a receiving side server.    
   
   
       2 . The cluster system according to  claim 1 , 
 wherein said standby computer transmits the received message to said receiving side server upon detecting a communication fault.    
   
   
       3 . The cluster system according to  claim 1 , 
 wherein said transmitting computer has a load management table for storing load information and CPU usage and memory usage values in normal run and estimate values of CPU usage and memory usage in case of fault are stored in the table.    
   
   
       4 . The cluster system according to  claim 1 , 
 wherein said transmitting computer classifies the load for a message to transmit in terms of CPU usage and memory usage, and selects said standby computer so that the loads across the computers upon a fault will be even, based on the classification.    
   
   
       5 . The cluster system according to  claim 4 , 
 wherein each computer included in said transmission side server cluster measures its CPU usage and memory usage and notifies other computers included in said transmission side server cluster of the measured values of CPU usage and memory usage, if change in the measured values from the previous measurements is equal to or more than a predetermined value.    
   
   
       6 . A fault recovery method for use in a cluster system, comprising the steps of: 
 selecting one of a plurality of computers constituting a transmission side server cluster as a transmitting computer;    selecting any of the computers other than said transmitting computer in said transmission side server cluster as a standby computer, based on load information; and; and    transmitting a message received by said transmitting computer to a receiving side server and the standby computer.    
   
   
       7 . The fault recovery method according to  claim 6 , further comprising a step in which said standby computer transmits the received message to the receiving side server upon detecting a communication fault.  
   
   
       8 . The fault recovery method according to  claim 6 , 
 wherein said load information is CPU usage or memory usage.    
   
   
       9 . The fault recovery method according to  claim 6 , 
 wherein said standby computer is selected, according to the transaction type of the message that said transmitting computer transmits.    
   
   
       10 . The fault recovery method according to  claim 9 , 
 wherein said message transaction type is determined by CPU usage or memory usage required for processing the message transaction.    
   
   
       11 . The fault recovery method according to  claim 6 , 
 wherein the step of selecting said standby computer comprises classifying the load for a message to transmit in terms of CPU usage and memory usage and selecting said standby computer so that the loads across the computers upon a fault will be even, based on the classification.    
   
   
       12 . The fault recovery method according to  claim 7 , 
 wherein said receiving side server records a plurality of checkpoints during an information processing process; if a fault occurs before a first checkpoint, the message transaction is re-executed from the beginning; if a fault occurs after the first checkpoint and subsequent, the transaction is re-executed from the most recent checkpoint.    
   
   
       13 . The cluster system according to  claim 1 , 
 wherein, when said transmitting computer receives an object transaction from a client, it sends the object transaction request to the receiving side server and transfers said object transaction request to said standby computer, and    wherein, when a fault occurs in said transmitting computer that received the object transaction, said standby computer takes over the transaction.    
   
   
       14 . A cluster system comprising: 
 a first computer cluster which receives a message from an external device;    a second compute cluster which receives the message from said first computer cluster; and    a third computer cluster which receives the message from said second compute cluster,    wherein a computer which is included in said first computer cluster and receives the message (which is hereinafter referred to as a “first transmitting computer”) selects a computer (hereinafter referred to as a “first standby computer”) from said first computer cluster, based on load information for every computer included in said first computer cluster,    wherein said first transmitting computer transmits the message to said first standby computer when transmitting the message to said second computer cluster,    wherein a computer which is included in said second computer cluster and receives the message (which is hereinafter referred to as a “second transmitting computer”) selects a computer (hereinafter referred to as a “second standby computer”) from said second computer cluster, based on load information for every computer included in said second computer cluster, and    wherein said second transmitting computer transmits the message to said second standby computer when transmitting the message to said third computer cluster.    
   
   
       15 . The cluster system according to  claim 14 , 
 wherein, if a fault occurs in said second transmitting computer, a computer which receives the message, included in said third computer cluster, transmits the message transaction processing result back to said second standby computer, and said first transmitting computer retransmits the message to said second standby computer.    
   
   
       16 . The cluster system according to  claim 15 , 
 wherein, if a fault occurs in said first transmitting computer, said second transmitting computer transmits the message transaction processing result back to said first standby computer.    
   
   
       17 . The cluster system according to  claim 16 , 
 wherein said load information is CPU usage or memory usage.    
   
   
       18 . The cluster system according to  claim 17 , 
 wherein said first and second standby computers are selected, according to the transaction type of the message that said first and second transmitting computers transmit.